This disclosure relates generally to online systems storing identity information for users, and in particular to inferring additional email addresses to match email addresses in a digest list.
Certain online systems, such as social networking systems, allow their users to connect to and to communicate with other online system users. Users may create profiles on such an online system that are tied to their identities and include information about the users, such as interests and demographic information. The users may be individuals or entities such as corporations or charities.
In some cases, a third party system provides the online system with a list of user identifying information. This information is typically hashed or obscured using a one-way transformation such that the online system may determine if local information matches this obscured information, but cannot recover any useful data from the obscured information directly.
The hashed user identifying information may typically include an email address, which includes a prefix, such as “john.doe” the at sign “@” and a domain, such as “acme.com.” However, the email address provided by the third party system for a third party user may not match an email address stored by the online system for a local user, although the local user indicated by the online system using that email address is the same as the third party user indicated by the third party system.